トルフェナミク酸のポリマー誘発ヘテロ核化:ペンタモルフの構造的調査
Vilmalí López-Mejías1, Jeff W Kampf, Adam J Matzger
1Department of Chemistry and the Macromolecular Science and Engineering Program, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, USA.
Journal of the American Chemical Society
|April 2, 2009
まとめ
トルフェナミク酸は,非ステロイド性抗炎症薬 (NSAID) であるが,少なくとも5つの固体形態があり,これまでの仮定に異議を唱えている. これらの新しいポリモルフは,ポリマー誘発型異核化 (PIHn) スクリーニングを使用して発見されました.
科学分野:
- 固体化学 固体化学
- マテリアルサイエンス 材料科学
- クリスタルグラフィーです.
背景:
- トルフェナミク酸 (TA) は,非ステロイド性抗炎症薬 (NSAID) である.
- 以前は,TAは2つの多形形 (二形形) のみ存在すると考えられていた.
- 固体状態の性質を理解することは,製薬開発にとって極めて重要です.
研究 の 目的:
- トルフェナミク酸の固体ポリモルフィズムを調査するために.
- ポリマー誘発ヘテロ核化 (PIHn) のポリモルフスクリーニングの有用性を調査する.
- TAの複雑な固体状態の振る舞いを特徴づけるために.
主な方法:
- ポリマー誘発ヘテロ核化 (PIHn) をポリモルフスクリーニングに使用した.
- 特徴付けのために高度な結晶学技術を使用した.
- 形状の変化と分子障害を分析した.
主要な成果:
- トルフェナミク酸の少なくとも5つの異なるポリモルフが特定されました.
- 形態の間で有意な分子乱れと空間群の多様性が観察されました.
- 非対称な単位内の分子数の変動を発見した.
- これらのポリモルフは狭い自由エネルギー窓 (~0.3 kcal/mol) の内に存在する.
結論:
- トルフェナミク酸は,独特の複雑な固体化学を表現しています.
- PIHnは,新しいポリモルフを発見するための効果的な技術です.
- TAの複雑さは,結晶構造予測モデルの優れた基準となる.
関連する概念動画
01:18Aromatic Hydrocarbon Cations: Structural Overview
Cycloheptatriene is a neutral monocyclic unsaturated hydrocarbon that consists of an odd number of carbon atoms and an intervening sp3 carbon in the ring. The three double bonds in the ring correspond to 6 π electrons, which is a Huckel number, and therefore satisfies the criteria of 4n + 2 π electrons. However, the intervening sp3 carbon disrupts the continuous overlap of p orbitals. As a result, cycloheptatriene is not aromatic.
Removing one hydrogen from the intervening CH2 group with both...
Removing one hydrogen from the intervening CH2 group with both...
00:57Cationic Chain-Growth Polymerization: Mechanism
The cationic polymerization mechanism consists of three steps: initiation, propagation, and termination. In the initiation step of the polymerization process, the π bond of a monomer gets protonated by the Lewis acid catalyst, which is formed from boron trifluoride and water. The protonation of the π bond generates a carbocation stabilized by the electron‐donating group. In the propagation step, the π bond of the second monomer acts as a nucleophile and attacks the generated carbocation,...
01:00Characteristics and Nomenclature of Homopolymers
Polymers that are made up of identical monomer units are called homopolymers. Only one repeating unit is involved in the construction of the homopolymer structure. For example, as depicted in Figure 1, polypropylene is a homopolymer constituted of propylene monomers. Here, the only repeating unit in the polymer chain is propylene.
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
01:17Ziegler–Natta Chain-Growth Polymerization: Overview
Ziegler–Natta polymerization is another form of addition or chain‐growth polymerization used for synthesizing linear polymers over branched polymers. The catalyst used for polymerization is the Ziegler–Natta catalyst, named after Karl Ziegler and Giulio Natta, who developed it in 1953. This catalyst is an organometallic complex of titanium tetrachloride and triethyl aluminum, with the active form of the catalyst being an alkyl titanium compound. Using the Ziegler–Natta catalyst, high molecular...
02:34Structural Isomerism
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...